Dyeing cellulose acetate



Patented Nov. 8, 1932 UNITED STATES PATENT OFFICE JAMES STEVENSON WILSONAND JOHN THOMAS, OF GRANGEMOU'I'H, SCOTLAND, ASSIGNORS TO SCOTTISH DYES,LIMITED, OF GRANGEMOUTH, SCOTLAND DYEING CELLULOSE ACETATE 'No Drawing.Application filed November 21, 1929, Serial No. 408,921, and in GreatBritain November 27, 1928.

Thisinvention relates to the dyeing of cellulose acetate with estersalts of vat dyestuffs.

The object of the present invention is to provide an improved ormodified process for the dyeing of cellulose acetate with ester salts ofvat dyestuffs.

As a result of researches, we have found that acetyl silk can be dyed bythe same method as cotton or wool, without the necessity for prolongedsteaming, or for in fact, in many cases, the application of any steamingprocess, although it may sometimes be necessary to scour the acetyl silkbefore dyeing, to remove gum or size used in Weaving or other 5processes.

The invention in brief consists in the application to the dyeing ofcellulose acetate or acetyl silk with ester salts of vat dyestufi's ofprocesses as used for the dyeing of cotton or wool or silk with suchbodies, scouring of the acetate when in the form of acetyl silk or thelike before dyeing being practised, when necessary to remove gum or sizeintroduced in connection with weaving or other processes.

The invention also consists in a method of dyeing cellulose acetate oracetyl silk which comprises the following steps Heating the bath,

Treatment of the acetyl silk,

Introduction of salt, and

Further treatment of the acetyl silk,

the shade subsequently being developed.

The invention also consists in a method of dyeing cellulose acetate oracetyl silk which cpnsists in a prolonged dyeing treatment.

The invention also consists in methods for dyeing cellulose acetate oracetyl silk substantially as herein described,and in products which mayhe obtained by these methods.

The following examples illustrate how the invention may be carried intoeffect. references to parts being to parts by weight.

' ly scoured and wetted-out acetyl silk is then entered. The material isworked for fifteen Example 1 This is an example of the dyeing ofcellulose acetate silk with Soledon jade green corresponding to Caledonjade green. Colour Index No. 1101.

For 10 parts of material, 1 part of soledon jade green is dissolved in400 parts of water. The bath is heated to 0., and the previousminutes atthis temperature, and then 100 per cent. of salt, calculated on theweight of the acetyl silk material, is added. 1 Dyeing is continued forone hour, and the material is then lifted, squeezed and developed byimmersion in a bath containing 1 per cent. of sodium nitrite and 1 percent. of hydrochloric acid. Development takes place immediately, atnormal temperatures, and the goods are rinsed, soaped and dried. Abright green shade is obtained which is fast to washing.

Example 2 Example 3 soledon brilliant purple RR corresponding to Caledonbrilliant purple RR. Colour Index No. 1104: is used in this example.

For 10 parts of acetyl silk. the bath is made up by dissolving 1 part ofsoledon brilliant purple BB in 400 parts of water with the ad- 90 ditionof one-eighth part of dispersol. The dye-bath is heated to 60 (3., andthe material entered. After fifteen minutes dyeing, 100 per cent. ofsalt, calculated on the weight of the silk, is added, and dyeingcontinued for another hour. The material is then removed teac er Ewample6 This example illustrates the various dyestufis which may be used, andthe resulting slides obtained on difierent kinds of acetyl s Method A.Method B. Method 0.

10 per cent on mlanese trlcot. 10 per cent on scetyl silk yarn. 3 percent on aoetyl silk cloth.

Indlgosol yellow HGG Pale gold-orange Pale gold-orange Golden yellowtint. Indlgosol golden yellow IGK Strong bright yellow Strong brightyellow- Medium bright yellow. Indlgoso; red HR Deep bright pinlr Deep brght pink Pale pink. Indigoso. violet AZB- Bright violet Deep br ghtviolet- Lilac shade. Indlgoso. green AB Deep bright green Deep brightgreen Pale apple green. Ind oso orange BIL-.. Medium apricot Mediumapr1eott1nt- Pale apricot. Indlgosol red HCR Medium brownish-red Mediumbrowmsh-red-- Pale pink. Indigosol smrlet H Bright nlnlr Bright pinkPale Indigosol HB Dee reddish-blue Deep bright violet. Pale violet.Indigosol 0R M ium blue Bright greyish-blue Pale grey-blue. IndigosolAZG Giune Greenish-blue Pale eenish-blue. Indlgosol 04B Bright blue Deepbright blue- Pele lue. Indigosol Greyish-blscln Greyish-blaclr Palegreenish-grey. Indigoso Pule grey-blue. Mediumbluish-gremn Grey tint.Indigoso pink HR Bright pink---" Bright mnk Pale pink. Indigoso Brightred-violet Bright red-violet Pale purple Ind 050.; 063 Gr ilne Deepbright blue Pale green 801 on jade green Deep bright green Deep brightgreen Pale green Boledon yellow G corresponding to Yale dull yellowMedium dull yellow Cream.

-glnle(llfi yellow G. Colour Index o. Boledon purple R mrrespondlngtoDeep bright purple Deep bright purple Pele purple gsletllpoig purple B.Colour Index and developed. Develo ment may be done as iollows:-The goos are passed first through a cold solution of 1 per cent. sodiumnitrite, and then through a cold solution of 1 per cent. hydrochloricacid, rinsed and soaped.

Example 4 Example 5 Indigosol golden yellow IGK is used in this pexample.

For 10 parts of acetyl silk cloth the bath is made up by dissolving 0.25part of Indigosol golden yellow IGK in 200 parts of water containing 4parts of sodium nitrite.

The dye-bath is heated to C., and the melted-out material entered. Afterfifteen minutes dyeing, 10 parts of salt are added and dyeing continuedfor forty-five minutes.

The material is then removed and developed I by immersion in a cold 1per cent. hydrochloric acid solution. After development the material isrinsed and soaped in a bath containing 1 per cent. soap at 40 C. forfifteen minutes. After soaping, the material is well rinsed and dried.

The above dyeing is obtained by the following method 1 part of colour iscarefully pasted with 1 part of a sulphonated castor oil. To this isadded 5 parts of water. The whole is added to 200 parts of water at 7 5C. 10 parts of the material, which has been previously well scoured in 1per cent. soap, 0.2 per cent. soda and 0.2 per cent, ammonia is enteredinto this liquor, and dyeing carried on for thirty minutes, while thetemperature is carefully raised to C. At the end of this period, 1 partof salt is added, and dyeing carried out for a further ten minutes, whena further 1.

part of salt is again added. The dyeing is then completed after afurther fifteen minutes. The temperature during the latter period ismaintained at 80 C. I

In the above method the amount of liquor used can be varied from 100parts to 400 arts according to the dyestufi used.

At the end of the dyeing operation the material is lifted, squeezed anddeveloped by immersion in a bath containing 2-per cent. of sodiumnitrite and 2 per cent. of sulphuric acid. Development takes placereadily at normal temperatures. The material is then lifted, rinsed,soaped in a bath containing 1 per cent. soap at 40 C. for fifteenminutes, rinsed and then dried.

General The colour index number and other identification of many of theIndigosol dyes listed may be found in the 1928 supplement of the Societyof Dyers and Colourists but to render this disclosure as complete aspossible perature between about C. and about aescgaei plement. Indigosolviolet AZB. According to the supplement to the Colour Index this is thesodium salt of the dlsuiphuric' ether of leuco alizarine indigovioletBZ. Colour Index No. 1217. See also supplement.

According to the Colour Index supplement this is the sodium salt of thedisulphuric ether of leuco hellndone red CR- According to the ColourIndex supplement, this is the sodium salt of the disulphuric ether ofleuco helindone scarlet B. According to the Colour Index supplement thisis derived from helindone ,blue B. Colour Index No.-1182, see alsoIndigosol orange Indigosol red HCB.

Iudigosol scarlet HB. I

lndigosol HB.

Indlgosol 0R.

supplement.

Indigosol AZG. Colour Index No. 1202, see also supplement.

Indigosol 043. Colour Index No. 1184, see also supplement.

According to the Colour Index supplement, this is the sodium salt of thedisulphuric ether of leuco thioindigo black B.

Indigosol black 18.

soledon jade green corresponds to Caledon jade green,

Colour Index No. 1101.

It is sometimes necessary to scour theacetyl silk before dyeing toremove gum or size used in weaving or other processes. The method isapplicable. not only to acetyl silk itself, but also to acetyl silk inadmixture with other materials. In such mixtures either solid shades orshades in which one material is dyed more deeply than the other can beobtained, the results depending on the conditions used.

In dyeing the union material containing natural silk and acetyl silk,greater depth may be obtained on the natural silk if the dyeing iscarried out for a short period only.

'In this specification and claims the term vat'dyestufi' enolic etherealsalt means a soluble salt of a vat dyestufi' containing one or moreacidic groups'attached to the oxygen atoms of the ketonic groups.

Having now described our invention, what we claim as new and desire tosecure by Letters Patent is 1. A process for dyeing cellulose acetatewhich consists in impregnating the aforesaid cellulose acetate with avat dyestufi' enolic ethereal salt by heating in an aqueous solution anddeveloping the vat dyestufi'.

2. A process for the dyeing of cellulose acetate, which consists inimmersing the cellulose acetate in a previously heated bath of a vatdyestufi enolic ethereal salt at a tem- C., and developing the vatdyestufl.

'3. A process for the dyeing of cellulose acetate which consists inimmersing the cellulose acetate in a previously heated bath of a vatdyestuli enolic ethereal salt, at a temperature of between about 50 C.and about 80 0., maintaining this temperature for about half an hour toabout one hour, and developing the vat dyestuff.

4. A process for the dyeing of cellulose acetate with vat dyestuflenolic ethereal salts which consists in suspending cellulose acetate ina previously heated aqueous saline solution of a vat dyestufi enolicethereal salt, which saline solution contains a salt chosenfrom thegroup consisting of sodium sulphate and sodium. chloride at atemperature of from about 50 C. to about 80 C. for from about half anhour'toabout the hour, and developing the vat dyestufi'.

5. A process for, the dyeing of cellulose acetate in the form of acetylsilk with rat dyestufi enolic ethereal salts which consists in scouringthe acetyl silk, suspending the thus scoured acetyl silk in apreviouslyheated aqueous saline solution of a vat dyestufl' enolicethereal salt, which saline solution contains a salt chosen from thegroup consisting of sodium sulphate and sodium chloride, at atemperature of between about 50 C. and about 80 C. for about half anhour to about one hour, and developing the vat dyestufi.

6. A process for dyeing'cellulose acetate, which consists in immersingthe cellulose acetate in a previously heated bath of a'vat dyestufl'enolic ethereal salt, and developing the vat dyestufi' in the presenceof a salt chosen from'the group consisting of sodium sulphate and sodiumchloride. s

7. A process for the dyeing of cellulose acetate which consists inimmersing the cellulose acetate in a previously heated bath of a vatdyestufi' enolic-ethereal salt, at a temperature of between about 50 C.and about 80 (3., maintaining thistemperature for about half an hour toabout one hour, adding a salt chosen from the group consisting of sodiumsulphate and sodium chloride during this stage and developing the vatdyestufi.

8. A process for the dyeing of cellulose acetate in the form of acetylsilk with vat dyestufi enolic ethereal salts which consists in scouringthe acetyl silk, suspending the thus scoured acetyl silk in a previouslyheated

